Assign a reason for each of the following:
(i) Ammonia is a stronger base than phosphine.
(ii) Sulphur in vapour state exhibits a paramagnetic behaviour.

Explanation

(i) Both ammonia and phosphine have pyramidal structure and both have a lone pair of electrons on N and P. Nitrogen being smaller than phosphorus, electron density of the lone pair on N in `NH_3` is more. Therefore, ammonia is a stronger base than phosphine.
(ii) Sulphur in the vapour phase exists as `S_2`. S has electronic configuration :

Due to presence of two unpaired electrons in antibonding p* orbitals, it is paramagnetic.